1. Field of the Invention
The present invention is in the field of oligonucleotide and cross-linking group conjugates and in the field of reagents adapted for making such conjugates. More particularly, the present invention is in the field of diaziridinyl-aryl and bis-[di(chloroethyl)amino]-aryl oligonucleotide conjugates that can effectively cross-link with both strands of double stranded DNA, and in the field of reagents for making such conjugates.
2. Brief Description of the Prior Art
Agents capable of alkylating nucleic acids have been known in the prior art and have found application in chemotherapy, diagnostic and related fields and as genetic probes for molecular biology. Several drugs used in cancer chemotherapy are bifunctional alkylating agents, particularly bifunctional nitrogen mustards. Examples of clinically used nitrogen mustards are mechlorethamine, melphalan and chlorambucil. These have been shown to form interstand DNA cross-links with a preference for the DNA sequence 5'-GNC (Millard et al. (1990) J. Am. Chem. Soc. 112, 2459-2460). Diaziridinyl benzoquinones are another class of bifunctional alkylating agents that have been shown to form interstrand cross-links in DNA. The efficiency of interstrand cross-linking was increased by reducing the quinone to hydroquinone (Haworth et al. Biochemistry 32, 12857-12863).
The concept of covalently linking one or more alkylating functions to an oligonucleotide (ODN) to accomplish alkylation of a target sequence in nucleic acid which is complementary to the ODN, has also been known in the art. For example, published PCT application WO 96/40711 (published on Dec. 19, 1996) describes oligonucleotides covalently linked to alkylating functions which alkylate complementary nucleic acid, and under certain conditions cross-link two strands of double stranded nucleic acid. U.S. Pat. No. 5,659,022 describes covalently linked conjugates of ODNs with a cyclopropapyrroloindole moiety that alkylate nucleic acid sequences which are complementary to the base sequence of the ODN.
In view of the potential therapeutic, diagnostic, genetic probe and related applications there is still a need in the art for chemical reagents that can form interstrand cross-links with DNA more efficiently. Moreover, there is a need for covalently bonded ODN-cross linker conjugates which efficiently cross-link with complementary DNA, and especially for triple-strand-forming (TFO) ODN-cross linker conjugates which efficiently form interstrand covalent bonds with both strands of targeted ds DNA. The present invention provides such chemical reagents, ODN-cross-linker conjugates as well as reagents for preparing the ODN-cross-linker conjugates.